Harnessing Ag nanofilm as an electrons transfer mediator for enhanced visible light photocatalytic performance of Ag@AgCl/Ag nanofilm/ZIF-8 photocatalyst

- A novel Ag@AgCl/Ag nanofilm/ZIF-8 photocatalyst was prepared.
- The Ag@AgCl/Ag nanofilm/ZIF-8 displays superior photocatalytic activity.
- Ag nanofilm was harnessed as an electrons transfer mediator for first time.
- The photocatalytic reaction mechanism of Ag@AgCl/Ag nanofilm/ZIF-8 was proposed.

An Ag@AgCl/Ag nanofilm/ZIF-8 composite photocatalyst was successfully constructed for the first time by loading Ag@AgCl and Ag nanofilm on the surface of ZIF-8 simultaneously via a simple deposition-photoreduction method. The formed Ag nanofilm was harnessed as a mediator to transfer photo-induced electrons from the plasmonic Ag@AgCl nanostructure to ZIF-8 for enhancing the photocatalytic reaction rate with visible light. The photocatalytic activity was evaluated by photocatalytic degradation of methylene blue (MB) under visible light irradiation. The first-order kinetic constant of MB degradation over Ag@AgCl/Ag nanofilm/ZIF-8 (14.762 h−1) was nearly 2 times of Ag@AgCl/ZIF-8 (7.932 h−1). The electrochemical impedance spectra, photoelectric conversion spectra and ESR DMPO-O2− species spectra revealed that AFZ had a lower resistance, higher photocurrent density and more generation of superoxide radical than those of AZ, meaning that the extended interface between Ag nanofilm and ZIF-8 could promote the quick electrons transfer and electron-hole pairs separation. This work provides a new type electrons transfer mediator in fabrication of efficient plasmonic photocatalysts.

Scheme of electron transfer from plasmonic metal to ZIF-8 (a) AZ and (b) AFZ.94